Effect of interferon-alpha on tyrosine hydroxylase and catecholamine levels in the brain of rats

We investigated the effect of interferon on tyrosine hydroxylase (TH) and c atecholamine levels in the brains of 12-week-old male Wistar rats. Interfer on-alpha (300,000 IU/kg/day, s.c.) was administered to rats for 7 days. Loc omotor activity of interferon-alpha-treated rats was significantly lower th an that of control rats. Norepinephrine and dopamine levels and TH activiti es in the cerebral cortex, hypothalamus and medulla oblongata of interferon -alpha-treated rats were significantly higher than those of control rats. N orepinephrine and dopamine levels and TH activities in the thalamus and hip pocampus were not different between interferon-alpha treated and control ra ts. These results suggest that interferon-alpha-induced depression may be r elated to change in the catecholamine synthetic pathway in the central nerv ous system. (C) 2000 Elsevier Science Inc. All rights reserved.